User manual

Chapter 6 Block Transfer Programming

ADVANCED MICRO CONTROLS INC.

This chapter describes the format of the data written to and read from the 2762-

17 using BTW and BTR instructions. It assumes familiarity with the setup and

operation of the 2762-17. Descriptions of the modules' parameters given in

chapter 1 are not repeated here. However, the default, minimum and maximum

values that can be programmed are listed. If you are not familiar with the

operation of the 2762-17, review chapters 1 and 2 before proceeding.

Block Transfer Writes

In addition to the keyboard, every 2762-17 parameter can be programmed with block

transfer writes (BTW). Programming from the keyboard can also be disabled. Follow these

guidelines when using block transfer writes.

BTW length is always 12 words. Do not set the length to zero when programming the BTW.

Any unused words in the block transfer should be considered reserved and set to zero.

All parameter values, (Full Scale Count, Linear Offset, etc.) must be transferred in binary

format. Before entering data in the data table set the radix to decimal.

Most of the 2762-17 parameters can exceed ±32,768. Therefore they require two words to

hold the data. The thousands digits must be transferred in the first word, the ones, tens, and

hundreds digits must be transferred in the second word. For example, a Full Scale Count of

368,640 would be transferred as 368 in the first word and 640 in the second word.

Negative values are transmitted in sign-magnitude format. The MSB of the first word of the

parameter is the sign bit. To enter a negative value set the data table radix to decimal and

enter the absolute value of the parameter. Next, switch the radix to binary and set the MSB

of the first word.

Once a block transfer write to the 2762-17 has completed, (i.e. The DONE Bit is set),

perform a block transfer read to input the status, position and tach data of the module.

Check the error bits and take appropriate action if an error has occurred.

If there is an error in the data sent to the 2762-17, the module responds by setting the

appropriate error bits and ignores all of the data sent to it with the block transfer write.

BTW Command Word

The first word of a BTW is the Command Word. As shown in figure 6.1, setting a bit in the

upper byte of the Command Word tells the 2762-17 which parameters are transferred in the

remaining eleven words. Note that only one bit can be set per block transfer. The meaning of

the lower byte changes, and is explained in later sections.

15 14 13 12 10 09 08 07 06 05 04 03 02 01 0011

Transducer Setup

Auxiliary Commands

Command Word

Positioning Setup

Preset Transducer Position

0000

RESERVED:

Must equal zero.

Fig. 6.1 Command Word Format